Laminated capacitor

ABSTRACT

In a laminated capacitor, one additional first internal electrode layer, which has its edge connected to the first external electrode as do the first internal electrode layers, is provided to one of the five first internal electrode layers so as to face one another via the second dielectric layer having a thickness smaller than the thickness of the first dielectric layer and not contributing to the formation of capacity, and one additional second internal electrode layer, which has its edge connected to the second external electrode as do the second internal electrode layers, is provided to one of the five second internal electrode layers so as to face one another via the third dielectric layer having a thickness smaller than the thickness of the first dielectric layer and not contributing to the formation of capacity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/442,673, filed Apr. 9, 2012, now U.S. Pat. No. 8,564,930, whichclaims priority to Japanese Patent Application No. 2011-089023, filedApr. 13, 2011, each disclosure of which is incorporated herein byreference in its entirety.

BACKGROUND

1. Field of the Invention

The present invention relates to a laminated capacitor.

2. Description of the Related Art

Laminated capacitors of small size such as 1608 (1.6 mm×0.8 mm), 1005(1.0 mm×0.5 mm) and 0603 (0.6 mm×0.3 mm) are inferior to large laminatedcapacitors in terms of bending strength, and therefore more vulnerableto cracks and breaking due to forces applied to the capacitor body whenthe capacitor body is installed on a circuit board, after it has beenmounted, and in other situations. Here, “bending strength” representsthe value measured in a test method conducted by supporting the externalelectrodes of the laminated capacitor and pushing the lengthwise centerof the laminated capacitor using a pressure jig, where, specifically,the load that causes the capacitor to break is indicated in gf, N, Pa orother units.

To improve the bending strength of a small laminated capacitor, areinforcement layer can be provided inside the capacitor body. There aretwo approaches regarding how to provide this reinforcement layer. One isto add a metal layer, which is different from an internal electrodelayer, as a reinforcement layer, while the other is to use an internalelectrode layer as a reinforcement layer.

It should be noted that structures that can be utilized according to theformer approach are disclosed in Patent Literatures 2 and 3 as mentionedbelow, while structures that can be utilized according to the latterapproach are disclosed in Patent Literatures 1, 4 and 5 as mentionedbelow, although these structures are not intended to improve the bendingstrength.

The structures disclosed in Patent Literatures 2 and 3 have a metallayer added to the top and bottom margins (where there is no internalelectrode layer) of a capacitor body. Since the added metal layers arenot connected to external electrodes, the bending strength does notimprove much.

The structure disclosed in Patent Literature 4 has two adjacent internalelectrode layers in a capacitor body connected to the same externalelectrode. This structure can improve the bending strength more than canthe structures disclosed in Patent Literatures 2 and 3, but because thetwo internal electrode layers are provided only on one externalelectrode side, the mechanical strength of the other external electrodeside of the capacitor body becomes lower than the mechanical strength onthe one external electrode side. Also, the thickness of the dielectriclayer present between the two internal electrode layers connected to thesame external electrode is equal to or greater than the thickness of thedielectric layer present between the two internal electrode layersconnected to different external electrodes, which increases the heightdimension of the laminated capacitor or decreases the number of internalconductive layers contributing to the formation of capacity if theaforementioned increase in height dimension is to be avoided, and theoverall capacity of the laminated capacitor will drop.

The structures disclosed in Patent Literatures 1 and 5 have anadditional internal electrode layer connected to one external electrodein such a way as to face the top internal electrode layer among theinternal electrode layers connected to the one external electrode, aswell as an additional internal electrode layer connected to the otherexternal electrode in such a way as to face the bottom internalelectrode layer among the internal electrode layers connected to theother external electrode. These structures can improve the bendingstrength more than can the structure disclosed in Patent Literature 4,but because the thicknesses of the dielectric layers (dielectric layersnot contributing to the formation of capacity) each present between theadditional internal electrode layer and the internal electrode layerfacing the additional internal electrode layer are the same as thethickness of the dielectric layer (dielectric layer contributing to theformation of capacity) present between the two internal electrode layersconnected to the different external electrodes, the height dimension ofthe laminated capacitor increases or the number of internal conductivelayers contributing to the formation of capacity decreases if theaforementioned increase in height dimension is to be avoided, and theoverall capacity of the laminated capacitor will drop.

Any discussion of problems and solutions involved in the related art hasbeen included in this disclosure solely for the purposes of providing acontext for the present invention, and should not be taken as anadmission that any or all of the discussion was known at the time theinvention was made.

PATENT LITERATURES

[Patent Literatures 1] Japanese Patent Laid-open No. Hei 07-335473

[Patent Literatures 2] Japanese Patent Laid-open No. Hei 08-181032

[Patent Literatures 3] Japanese Patent Laid-open No. Hei 08-316086

[Patent Literatures 4] Japanese Patent Laid-open No. Hei 10-270281

[Patent Literatures 5] Japanese Patent Laid-open No. 2009-224569

SUMMARY

An object of the present invention is to provide a laminated capacitorcapable of improving bending strength while suppressing an increase inheight dimension.

To achieve the aforementioned object, the present invention provides alaminated capacitor characterized in that:

a plurality of first internal electrode layers used as one polarity anda plurality of second internal electrode layers used as the otherpolarity are facing one another via a first dielectric layercontributing to the formation of capacity and also arranged alternatelyvia the first dielectric layer; and

the edges of the plurality of first internal electrode layers areconnected to a first external electrode used as one polarity, while theedges of the plurality of second internal electrode layers are connectedto a second external electrode used as the other electrode;

wherein at least one additional first internal electrode layer, whichhas its edge connected to the first external electrode as do the firstinternal electrode layers, is provided to at least one of the pluralityof first internal electrode layers so as to face one another via asecond dielectric layer having a thickness smaller than the thickness ofthe first dielectric layer and not contributing to the formation ofcapacity; and

wherein at least one additional second internal electrode layer, whichhas its edge connected to the second external electrode as do the secondinternal electrode layers, is provided to at least one of the pluralityof second internal electrode layers so as to face one another via athird dielectric layer having a thickness smaller than the thickness ofthe first dielectric layer and not contributing to the formation ofcapacity.

According to the present invention, at least one additional firstinternal electrode layer, which has its edge connected to the firstexternal electrode as do the first internal electrode layers, isprovided to at least one of the plurality of first internal electrodelayers so as to face one another via a second dielectric layer having athickness smaller than the thickness of the first dielectric layer andnot contributing to the formation of capacity, and at least oneadditional second internal electrode layer, which has its edge connectedto the second external electrode as do the second internal electrodelayers, is provided to at least one of the plurality of second internalelectrode layers so as to face one another via a third dielectric layerhaving a thickness smaller than the thickness of the first dielectriclayer and not contributing to the formation of capacity.

In other words, the structure is such that the at least one additionalfirst internal electrode layer is used as a reinforcement layer, whilethe at least one additional second internal electrode layer is used as areinforcement layer, and therefore the presence of these reinforcementlayers allows for improvement of the bending strength of the laminatedcapacitor.

Also, the structure is such that the at least one additional firstinternal electrode layer is connected to the first external electrode,while the at least one additional second internal electrode layer isconnected to the second external electrode, and therefore the mechanicalstrength on the first external electrode side of the capacitor body isbalanced with the mechanical strength on the second external electrodeside, which allows for improvement of the bending strength of thelaminated capacitor in a more precise fashion.

Furthermore, the thickness of the second dielectric layer (dielectriclayer not contributing to the formation of capacity) present between theat least one additional first internal electrode layer and the firstinternal electrode layer facing the additional first internal electrodelayer, and thickness of the third dielectric layer (dielectric layer notcontributing to the formation of capacity) present between the at leastone additional second internal electrode layer and the second internalelectrode layer facing the additional second internal electrode layer,are smaller than the thickness of the first internal dielectric layer(dielectric layer contributing to the formation of capacity) presentbetween the first internal conductive layer and second conductive layer,and this helps suppress the increase in the height dimension of thelaminated capacitor as much as possible.

The aforementioned object and other objects,constitution/characteristics and operation/effects of the presentinvention are made clear by the following explanations and attacheddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this invention will now be described withreference to the drawings of preferred embodiments which are intended toillustrate and not to limit the invention. The drawings are greatlysimplified for illustrative purposes and are not necessarily to scale.

FIG. 1 is an external perspective view of a laminated capacitor to whichthe present invention is applied (first embodiment).

FIG. 2 is an enlarged view of FIG. 1, showing the section cut along lineS1-S1.

FIG. 3 is an enlarged view of FIG. 1, showing the section cut along lineS2-S2.

FIG. 4 is a partially enlarged view of FIG. 2.

FIG. 5 is a section view corresponding to FIG. 2 (enlarged section viewshowing one lengthwise half), showing an example of structural variationof the laminated capacitor shown in FIGS. 1 to 4.

FIG. 6 is a section view corresponding to FIG. 2, showing a laminatedcapacitor to which the present invention is applied (second embodiment).

FIG. 7 is a section view corresponding to FIG. 5, showing an example ofstructural variation of the laminated capacitor shown in FIG. 6.

FIG. 8 is a section view corresponding to FIG. 2, showing a laminatedcapacitor to which the present invention is applied (third embodiment).

FIG. 9 is a section view corresponding to FIG. 5, showing an example ofstructural variation of the laminated capacitor shown in FIG. 8.

DESCRIPTION OF THE SYMBOLS

10, 10′, 20, 20′, 30, 30′—Laminated capacitor

11—Capacitor body

12—First external electrode

13—Second external electrode

14—Dielectric part

15—First internal electrode layer (including the additional firstinternal electrode layer)

16—Second internal electrode layer (including the additional secondinternal electrode layer)

DL1—First dielectric layer

DL2—Second dielectric layer

DL3—Third dielectric layer

DETAILED DESCRIPTION

The present invention is explained with reference to typical embodimentswhich are not intended to limit the present invention.

First Embodiment

FIGS. 1 to 4 show a laminated capacitor 10 to which the presentinvention is applied (first embodiment).

<Structure of Laminated Capacitor 10>

First, the structure of the laminated capacitor 10 is explained. In thefollowing explanations, left, right, front, back, top and bottom of thedrawing of FIG. 2 refer to front, rear, left, right, top and bottom ofthe capacitor, respectively, and the same applies to the correspondingdirections of other figures, for the purpose of convenience ofexplanation.

The laminated capacitor 10 forms a rough rectangular solid shape havingthe relationships of length dimension L>width dimension W>heightdimension H, where the specific length dimension L is 1.0 mm, widthdimension W is 0.5 mm, and height dimension H is 0.15 mm.

The laminated capacitor 10 has a capacitor body 11 that forms a roughrectangular solid body having the same dimensional relationships asmentioned above, a first external electrode 12 that continuously coversthe front face, and front parts of the left and right faces and top andbottom faces, of the capacitor body 11, and a second external electrode13 that continuously covers the rear face, and rear parts of the leftand right faces and top and bottom faces, of the capacitor body 11. Thefirst external electrode 12 is used as one polarity, while the secondexternal electrode 13 is used as the other polarity.

The capacitor body 11 is constituted by a dielectric part 14 made ofceramics, a total of six first internal electrode layers 15 that aremade of metal and provided in the dielectric part 14, and a total of sixsecond internal electrode layers 16 that are made of the same materialas the first internal electrode layers 15 and provided in the dielectricpart 14. The specific name of the material of the dielectric part 14 isbarium titanate, while the specific name of the material of the firstinternal electrode layers 15 and second internal electrode layers 16 isnickel.

It should be noted that the number of first internal electrode layers 15and the number of second internal electrode layers 16 are greater than 6in actuality, but the following explains the capacitor body 11 byassuming that the number of first internal electrode layers 15 andnumber of second internal electrode layers 16 are both 6, for thepurpose of convenience of illustration.

Each first internal electrode layer 15 forms a rectangle whose lengthdimension and width dimension are smaller than the length dimension andwidth dimension of the capacitor body 11, while each second internalelectrode layer 16 forms a rectangle whose length dimension and widthdimension are roughly the same as those of the first internal electrodelayer 15. The thickness of each first internal electrode layer 15 is thesame as the thickness of each second internal electrode layer 16, andthis thickness is 0.5 to 3.0 μm, for example.

The front edge of each first internal electrode layer 15 is electricallyconnected to the first external electrode 12, while the rear edge ofeach second internal electrode layer 16 is electrically connected to thesecond external electrode 13. In other words, each first internalelectrode layer 15 is used as one polarity, while each second internalelectrode layer 16 is used as the other polarity.

Five first internal electrode layers 15 among the total of six firstinternal electrode layers 15, and five second internal electrode layers16 among the total of six second internal electrode layers 16, arebasically facing one another via a first dielectric layer DL1contributing to the formation of capacity and also arranged alternatelyvia the first dielectric layer DL1. The thickness td1 of each firstdielectric layer DL1 is 2.0 to 6.0 μm, for example.

Also, one additional first internal electrode layer 15 is provided in amanner facing the third first internal electrode layer 15 from the topvia a second dielectric layer DL2 not contributing to the formation ofcapacity. Additionally, one additional second internal electrode layer16 is provided in a manner facing the third second internal electrodelayer 16 from the top via a third dielectric layer DL3 not contributingto the formation of capacity. In other words, one additional firstinternal electrode layer 15 and one additional second internal electrodelayer 16 are provided for the first internal electrode layer 15 andsecond internal electrode layer 16, respectively, that are present sideby side at the very center of the capacitor body 11.

The thickness td2 of the second dielectric layer DL2 and thickness td3of the third dielectric layer DL3 are roughly the same and smaller thanthe thickness td1 of the first dielectric layer DL1. Preferably therelationship of the thickness td2 of the second dielectric layer DL2,thickness td3 of the third dielectric layer DL3 and thickness td1 of thefirst dielectric layer DL1 should satisfy td2≅td3<⅔×td1. The thicknesstd2 of the second dielectric layer DL2 and thickness td3 of the thirddielectric layer DL3 are 0.5 to 3.0 μm, for example, and closer to thethickness of each first internal electrode layer 15 and thickness ofeach second internal electrode layer 16 than to the thickness td1 of thefirst dielectric layer DL1.

It should be noted that because the thickness td2 of the seconddielectric layer DL2 and thickness td3 of the third dielectric layer DL3are smaller than the thickness td1 of the first dielectric layer DL1, inthe sintering process of heat treatment in the manufacturing methodexplained later, the baking of the second dielectric layer DL2sandwiched between two first internal electrode layers 15 and the bakingof the third dielectric layer DL3 sandwiched between two second internalelectrode layers 16 progress more quickly than the baking of thethickness td1 of the first dielectric layer DL1 present between thefirst internal electrode layer 15 and second internal electrode layer16, and from this difference in baking speeds the strength of the seconddielectric layer DL2 and strength of the third dielectric layer DL3 areconsidered higher than the strength of the first dielectric layer DL1.

The first external electrode 12 and second external electrode 13, whichare not shown, have a multi-layer structure comprising a base film and asurface film covering the base film. The specific name of the materialof the base film is nickel and its thickness is 1.0 to 3.0 μm, forexample, while the specific name of the material of the surface film istin and its thickness is 0.5 to 1.5 μm, for example.

The capacity of the laminated capacitor 10 is formed between the firstinternal conductive layer 15 and second conductive layer 16 that arefacing each other via the first dielectric layer DL1 contributing to theformation of capacity, among the total of six first internal electrodelayers 15 and total of six second internal electrode layers 16.

<Method of Manufacturing Laminated Capacitor 10>

Next, the method of manufacturing the laminated capacitor 10 isexplained. Take note that the manufacturing method explained here isonly an example and it goes without saying that the laminated capacitor10 can also be manufactured by changing the composition of thedielectric slurry mentioned below or composition of the conductive pastementioned below, or by simultaneously applying heat treatment to theunsintered chip mentioned below and base film paste mentioned below.

Prior to manufacturing, a dielectric slurry containing barium titanatepowder and polyvinyl butyral (binder), ethanol and water (solvent), andphosphate ester (dispersant), all at a specified weight ratio, isprepared. Also, a conductive paste containing nickel powder, bariumtitanate powder and polyvinyl butyral (binder), ethanol (solvent), andphosphate ester (dispersant), all at a specified weight ratio, is alsoprepared.

Next, a doctor blade or other coating machine is used to apply thedielectric slurry to a specified thickness onto a base film made of PET,etc., and then the slurry is dried to produce a first dielectric sheet,and the same method is followed to produce a second dielectric sheetwhich is thinner than the first dielectric sheet.

Next, a screen printer or other printer is used to print the conductivepaste onto the first dielectric sheet at a specified thickness, shapeand layout, and then the paste is dried to produce a first laminatedsheet for the first internal electrode layer 15, and the same method isfollowed to produce a second laminated sheet for the second internalelectrode layer 16.

Also, a screen printer or other printer is used to print the conductivepaste onto the second dielectric sheet at a specified thickness, shapeand layout, and then the paste is dried to produce a third laminatedsheet for the additional first internal electrode layer 15, and the samemethod is followed to produce a fourth laminated sheet for theadditional second internal electrode layer 16.

Next, a specified number of first dielectric sheets are stacked, asecond laminated sheet is stacked on top, a first laminated sheet isstacked on top, a second laminated sheet is stacked on top, a firstlaminated sheet is stacked on top, a second laminated sheet is stackedon top, a fourth laminated sheet is stacked on top, a first laminatedsheet is stacked on top, a third laminated sheet is stacked on top, asecond laminated sheet is stacked on top, a first laminated sheet isstacked on top, a second laminated sheet is stacked on top, a firstlaminated sheet is stacked on top, and a specified number of firstdielectric sheets are stacked on top, after which a hydrostatic press orother press machine is used to apply pressure to the entire stack inorder to pressure-bond the sheets together to produce a sheet laminate.

Next, a dicing machine or other cutting machine is used to cut the sheetlaminate to a size corresponding to the capacitor body 11, to produce anunsintered chip.

Next, a sintering furnace or other heating apparatus is used toheat-treat a number of unsintered chips all at the same time accordingto a specified temperature profile. This heat treatment includes thebinder removal process and sintering process, and the capacitor body 11is produced after these processes.

Next, a dipper or other coating apparatus is used to apply theconductive paste onto both of the lengthwise ends of the capacitor body11 and the paste is dried. Thereafter, a sintering furnace or otherheating apparatus is used to heat-treat a number of capacitor bodies 11coated with the conductive paste, all at the same time according to aspecified temperature profile, to produce a base film (nickel film) forthe first external electrode 12 and base film (nickel film) for thesecond external electrode 13.

Next, an electroplating bath or other plating apparatus is used to platethe capacitor bodies 11 on which the base films have been produced, allat the same time, to produce a surface film (tin film) for the firstexternal electrode 12 and surface film (tin film) for the secondexternal electrode 13. Now, the laminated capacitor 10 has beenproduced.

<Effects of Laminated Capacitor 10>

Next, the effects of the laminated capacitor 10 are explained.

(1) One additional first internal electrode layer 15, which has its edgeconnected to the first external electrode 12 as do the first internalelectrode layers 15, is provided to one of the five first internalelectrode layers 15 so as to face one another via the second dielectriclayer DL2 having a thickness td2 smaller than the thickness td1 of thefirst dielectric layer DL1 and not contributing to the formation ofcapacity, and one additional second internal electrode layer 16, whichhas its edge connected to the second external electrode 13 as do thesecond internal electrode layers 16, is provided to one of the fivesecond internal electrode layers 16 so as to face one another via thethird dielectric layer DL3 having a thickness td3 smaller than thethickness td1 of the first dielectric layer DL1 and not contributing tothe formation of capacity.

In other words, the structure is such that the one additional firstinternal electrode layer 15 is used as a reinforcement layer, while theone additional second internal electrode layer 16 is used as areinforcement layer, and therefore the presence of these reinforcementlayers allows for improvement of the bending strength of the laminatedcapacitor 10.

Also, the structure is such that the additional first internal electrodelayer 15 is connected to the first external electrode 12, while theadditional second internal electrode layer 16 is connected to the secondexternal electrode 13, and therefore the mechanical strength on thefirst external electrode 12 side of the capacitor body 11 is balancedwith the mechanical strength on the second external electrode 13 side,which allows for improvement of the bending strength of the laminatedcapacitor 10 in a more precise fashion.

Furthermore, the thickness td2 of the second dielectric layer DL2(dielectric layer not contributing to the formation of capacity) presentbetween the additional first internal electrode layer 15 and the firstinternal electrode layer 15 facing the additional first internalelectrode layer, and thickness td3 of the third dielectric layer DL3(dielectric layer not contributing to the formation of capacity) presentbetween the additional second internal electrode layer 16 and the secondinternal electrode layer 16 facing the additional second internalelectrode layer, are smaller than the thickness td1 of the firstinternal dielectric layer DL1 (dielectric layer contributing to theformation of capacity) present between the first internal conductivelayer 15 and second conductive layer 16, and this helps suppress theincrease in the height dimension H of the laminated capacitor 10 as muchas possible.

(2) The strength of the second dielectric layer DL2 (dielectric layernot contributing to the formation of capacity) present between theadditional first internal electrode layer 15 and the first internalelectrode layer 15 facing the additional first internal electrode layer,and strength of the third dielectric layer DL3 (dielectric layer notcontributing to the formation of capacity) present between theadditional second internal electrode layer 16 and the second internalelectrode layer 16 facing the additional second internal electrodelayer, are higher than the strength of the first internal dielectriclayer DL1 (dielectric layer contributing to the formation of capacity)present between the first internal conductive layer 15 and secondconductive layer 16, and this allows for improvement of the bendingstrength of the laminated capacitor 10 in a more reliable manner, withthe second dielectric layer DL2 and third dielectric layer DL3 assumingthe role of reinforcement layers.

<Verification of Bending Strength of Laminated Capacitor 10>

Note that with the laminated capacitor of the size (length dimension Lof 1.0 mm, width dimension W of 0.5 mm and height dimension H of 0.15mm) explained in <Structure of Laminated Capacitor 10> above, themeasured bending strength must be 100 gf or more in order to preventcracks and breaking due to forces applied to the capacitor body when thecapacitor body is installed on a circuit board, after it has beenmounted, and in other situations, regardless of the total number ofinternal electrode layers, capacity of the laminated capacitor, and thelike.

In light of the aforementioned situation, a prototype of the laminatedcapacitor 10 was produced based on the number of first internalelectrode layers 15 (including the additional first internal electrodelayer 15) being 19, the number of second internal electrode layers 16(including the additional second internal electrode layer 16) being 19,the thickness of each first internal electrode layer 15 and thethickness of each second internal electrode layer 16 being 0.8 μm, thethickness td1 of each first dielectric layer DL1 being 2.3 μm, and thethickness td2 of the second dielectric layer DL2 and thickness td3 ofthe third dielectric layer DL3 being 0.9 μm, and when the bendingstrength of this prototype was measured, it was 180 gf.

Another prototype of the laminated capacitor 10 was produced based onthe number of first internal electrode layers 15 (including theadditional first internal electrode layer 15) being 19, the number ofsecond internal electrode layers 16 (including the additional secondinternal electrode layer 16) being 19, the thickness of each firstinternal electrode layer 15 and the thickness of each second internalelectrode layer 16 being 0.8 μm, the thickness td1 of each firstdielectric layer DL1 being 2.3 μm, and the thickness td2 of the seconddielectric layer DL2 and the thickness td3 of the third dielectric layerDL3 being 1.4 μm, and when the bending strength of this prototype wasmeasured, it was 140 gf.

On the other hand, a prototype of a laminated capacitor for comparisonwas produced based on the number of first internal electrode layers 15(no additional first internal electrode layer 15) being 19, the numberof second internal electrode layers 16 (no additional second internalelectrode layer 16) being 19, the thickness of each first internalelectrode layer 15 and the thickness of each second internal electrodelayer 16 being 0.8 μm, and the thickness td1 of each first dielectriclayer DL1 being 2.3 μm, or specifically a prototype of general structurehaving no additional first internal electrode layer 15, additionalsecond internal electrode layer 16, second dielectric layer DL2 or thirddielectric layer DL3, and when the bending strength of this prototypewas measured, it was 95 gf.

<Examples of Structural Variation of Laminated Capacitor 10>

Next, examples of structural variation of the laminated capacitor 10 areexplained.

(1) FIGS. 1 to 4 show a laminated capacitor 10 having one additionalfirst internal electrode layer 15 and second dielectric layer DL2, aswell as one additional second internal electrode layer 16 and thirddielectric layer DL3, but the same effects as mentioned above can beachieved with the laminated capacitor 10′ shown in FIG. 5 which has two(or three or more) additional first internal electrode layers 15 andsecond dielectric layers DL2, as well as two (or three or more)additional second internal electrode layers 16 and third dielectriclayers DL3.

Increasing the number of additional first internal electrode layers 15and second dielectric layers DL2 and the number of additional secondinternal electrode layers 16 and third dielectric layers DL3 improvesthe bending strength of the laminated capacitor 10′ further, but it alsoincreases the height dimension H of the laminated capacitor 10′, andtherefore, in reality, the number of additional first internal electrodelayers 15 and second dielectric layers DL2 and the number of additionalsecond internal electrode layers 16 and third dielectric layers DL3 mustbe carefully selected, by considering the amount of increase in theheight dimension H of the laminated capacitor 10′.

(2) FIGS. 1 to 4 show a laminated capacitor 10 where the number of firstinternal electrode layers 15 (including the additional first internalelectrode layer 15) and the number of second internal electrode layers16 (including the additional second internal electrode layer 16) areboth 6, for the purpose of convenience, but, as stated earlier, thenumber of first internal electrode layers 15 and the number of secondinternal electrode layers 16 are actually greater than 6 and the sameeffects as mentioned above can be achieved when both are greater than 6.

(3) FIGS. 1 to 4 show a laminated capacitor 10 whose length dimension Lis 1.0 mm, width dimension W is 0.5 mm and height dimension H is 0.15mm, but the same effects as mentioned above can be achieved with alaminated capacitor whose length dimension L, width dimension W andheight dimension H are other than the aforementioned values, and thesame effects as mentioned above can also be achieved with a laminatedcapacitor having the relationship of (length dimension L)>(widthdimension W)=(height dimension H).

(4) FIGS. 1 to 4 show an example of the thickness of each first internalelectrode layer 15 and thickness of each second internal electrode layer16 being 0.5 to 3.0 μm, an example of the thickness td1 of each firstdielectric layer DL1 being 2.0 to 6.0 μm, and an example of thethickness td2 of the second dielectric layer DL2 and the thickness td3of the third dielectric layer DL3 being 0.5 to 3.0 μm, but these valuescan be changed as deemed appropriate according to the aforementionednumber of first internal electrode layers 15 and the number of secondinternal electrode layers 16, the aforementioned size of the laminatedcapacitor 10 and the capacity required of the laminated capacitor 10,and so on, and even when they are changed, the same effects as mentionedabove can be achieved.

(5) FIGS. 1 to 4 show an example of the material of the dielectric part14 (including the first dielectric layer DL1, second dielectric layerDL2 and third dielectric layer DL3) being barium titanate, an example ofthe material of the first internal electrode layer 15 and secondinternal electrode layer 16 being nickel, an example of the material ofthe base film for the first external electrode 12 and second externalelectrode 13 being nickel, and an example of the material of the surfacefilm being tin, but the same effects as mentioned above can be achievedeven when the dielectric part 14 is made of a dielectric substance otherthan barium titanate, when the first internal electrode layer 15 and thesecond internal electrode layer 16 are made of a metal or alloy otherthan nickel, when the base film for the first external electrode 12 andthe second external electrode 13 is made of a metal or alloy other thannickel, and when the surface film is made of a metal or alloy other thantin.

Second Embodiment

FIG. 6 shows a laminated capacitor 20 to which the present invention isapplied (second embodiment).

<Structure of Laminated Capacitor 20>

The laminated capacitor 20 is structurally different from the laminatedcapacitor 10 (first embodiment) in that one additional first internalelectrode layer 15 is provided in a manner facing the second firstinternal electrode layer 15 from the top via the second dielectric layerDL2 not contributing to the formation of capacity, while one additionalsecond internal electrode layer 16 is provided in a manner facing thefourth second internal electrode layer 16 from the top (second from thebottom) via the third dielectric layer DL3 not contributing to theformation of capacity. Other parts of the structure are the same asthose of the laminated capacitor 10 (first embodiment) and therefore notexplained.

The manufacturing method of this laminated capacitor 20 is the same asthat of the laminated capacitor 10 (first embodiment), except that thestacking order of the first through fourth laminated sheets is changed,and therefore not explained. Also, the effects achieved with thislaminated capacitor 20 are the same as those achieved with the laminatedcapacitor 10 (first embodiment) and therefore not explained.

<Examples of Structural Variation of Laminated Capacitor 20>

Next, examples of structural variation of the laminated capacitor 20 areexplained.

(1) FIG. 6 shows a laminated capacitor 20 having one additional firstinternal electrode layer 15 and second dielectric layer DL2, as well asone additional second internal electrode layer 16 and third dielectriclayer DL3, but the same effects as mentioned above can be achieved withthe laminated capacitor 20′ shown in FIG. 7 which has two (or three ormore) additional first internal electrode layers 15 and seconddielectric layers DL2, as well as two (or three or more) additionalsecond internal electrode layers 16 and third dielectric layers DL3.

Increasing the number of additional first internal electrode layers 15and second dielectric layers DL2 and the number of additional secondinternal electrode layers 16 and third dielectric layers DL3 improvesthe bending strength of the laminated capacitor 20′ further, but it alsoincreases the height dimension H of the laminated capacitor 20′, andtherefore, in reality, the number of additional first internal electrodelayers 15 and second dielectric layers DL2 and the number of additionalsecond internal electrode layers 16 and third dielectric layers DL3 mustbe carefully selected, by considering the amount of increase in theheight dimension H of the laminated capacitor 20′.

(2) FIG. 6 shows a laminated capacitor 20 where the number of firstinternal electrode layers 15 (including the additional first internalelectrode layer 15) and the tnumber of second internal electrode layers16 (including the additional second internal electrode layer 16) areboth 6, for the purpose of convenience, but, as stated earlier, thenumber of first internal electrode layers 15 and the number of secondinternal electrode layers 16 are actually greater than 6 and the sameeffects as mentioned above can be achieved when both are greater than 6.

(3) FIG. 6 shows a laminated capacitor 20 whose length dimension L is1.0 mm, width dimension W is 0.5 mm and height dimension H is 0.15 mm,but the same effects as mentioned above can be achieved with a laminatedcapacitor whose length dimension L, width dimension W and heightdimension H are other than the aforementioned values, and the sameeffects as mentioned above can also be achieved with a laminatedcapacitor having the relationship of (length dimension L)>(widthdimension W)=(height dimension H).

(4) FIG. 6 shows an example of the thickness of each first internalelectrode layer 15 and the thickness of each second internal electrodelayer 16 being 0.5 to 3.0 μm, an example of the thickness td1 of eachfirst dielectric layer DL1 being 2.0 to 6.0 μm, and an example of thethickness td2 of the second dielectric layer DL2 and the thickness td3of the third dielectric layer DL3 being 0.5 to 3.0 μm, but these valuescan be changed as deemed appropriate according to the aforementionednumber of first internal electrode layers 15 and the number of secondinternal electrode layers 16, the aforementioned size of the laminatedcapacitor 20 and capacity required of the laminated capacitor 20, and soon, and even when they are changed, the same effects as mentioned abovecan be achieved.

(5) FIG. 6 shows an example of the material of the dielectric part 14(including the first dielectric layer DL1, second dielectric layer DL2and third dielectric layer DL3) being barium titanate, an example of thematerial of the first internal electrode layer 15 and second internalelectrode layer 16 being nickel, an example of the material of the basefilm for the first external electrode 12 and second external electrode13 being nickel, and an example of the material of the surface filmbeing tin, but the same effects as mentioned above can be achieved evenwhen the dielectric part 14 is made of a dielectric substance other thanbarium titanate, when the first internal electrode layer 15 and secondinternal electrode layer 16 are made of a metal or alloy other thannickel, when the base film for the first external electrode 12 andsecond external electrode 13 is made of a metal or alloy other thannickel, and when the surface film is made of a metal or alloy other thantin.

Third Embodiment

FIG. 8 shows a laminated capacitor 30 to which the present invention isapplied (third embodiment).

<Structure of Laminated Capacitor 30>

The laminated capacitor 30 is structurally different from the laminatedcapacitor 10 (first embodiment) in that one additional first internalelectrode layer 15 is provided in a manner facing the top (outermost)first internal electrode layer 15 via the second dielectric layer DL2not contributing to the formation of capacity, while one additionalsecond internal electrode layer 16 is provided in a manner facing thefifth second internal electrode layer 15 from the top (bottom, oroutermost) via the third dielectric layer DL3 not contributing to theformation of capacity. Other parts of the structure are the same asthose of the laminated capacitor 10 (first embodiment) and therefore notexplained.

The manufacturing method of this laminated capacitor 30 is the same asthat of the laminated capacitor 10 (first embodiment), except that thestacking order of the first through fourth laminated sheets is changed,and therefore not explained. Also, the effects achieved with thislaminated capacitor 30 are the same as those achieved with the laminatedcapacitor 10 (first embodiment) and therefore not explained.

<Examples of Structural Variation of Laminated Capacitor 30>

Next, examples of structural variation of the laminated capacitor 30 areexplained.

(1) FIG. 8 shows a laminated capacitor 30 having one additional firstinternal electrode layer 15 and second dielectric layer DL2, as well asone additional second internal electrode layer 16 and third dielectriclayer DL3, but the same effects as mentioned above can be achieved withthe laminated capacitor 30′ shown in FIG. 9 which has two (or three ormore) additional first internal electrode layers 15 and seconddielectric layers DL2, as well as two (or three or more) additionalsecond internal electrode layers 16 and third dielectric layers DL3.

Increasing the number of additional first internal electrode layers 15and second dielectric layers DL2 and the number of additional secondinternal electrode layers 16 and third dielectric layers DL3 improvesthe bending strength of the laminated capacitor 30′ further, but it alsoincreases the height dimension H of the laminated capacitor 30′, andtherefore, in reality, the number of additional first internal electrodelayers 15 and second dielectric layers DL2 and the number of additionalsecond internal electrode layers 16 and third dielectric layers DL3 mustbe carefully selected, by considering the amount of increase in theheight dimension H of the laminated capacitor 30′.

(2) FIG. 8 shows a laminated capacitor 30 where the number of firstinternal electrode layers 15 (including the additional first internalelectrode layer 15) and the number of second internal electrode layers16 (including the additional second internal electrode layer 16) areboth 6, for the purpose of convenience, but, as stated earlier, thenumber of first internal electrode layers 15 and the number of secondinternal electrode layers 16 are actually greater than 6 and the sameeffects as mentioned above can be achieved when both are greater than 6.

(3) FIG. 8 shows a laminated capacitor 30 whose length dimension L is1.0 mm, width dimension W is 0.5 mm and height dimension H is 0.15 mm,but the same effects as mentioned above can be achieved with a laminatedcapacitor whose length dimension L, width dimension W and heightdimension H are other than the aforementioned values, and the sameeffects as mentioned above can also be achieved with a laminatedcapacitor having the relationship of (length dimension L)>(widthdimension W)=(height dimension H).

(4) FIG. 8 shows an example of the thickness of each first internalelectrode layer 15 and the thickness of each second internal electrodelayer 16 being 0.5 to 3.0 μm, an example of the thickness td1 of eachfirst dielectric layer DL1 being 2.0 to 6.0 μm, and an example of thethickness td2 of the second dielectric layer DL2 and the thickness td3of the third dielectric layer DL3 being 0.5 to 3.0 μm, but these valuescan be changed as deemed appropriate according to the aforementionednumber of first internal electrode layers 15 and the number of secondinternal electrode layers 16, the aforementioned size of the laminatedcapacitor 30 and the capacity required of the laminated capacitor 30,and so on, and even when they are changed, the same effects as mentionedabove can be achieved.

(5) FIG. 8 shows an example of the material of the dielectric part 14(including the first dielectric layer DL1, second dielectric layer DL2and third dielectric layer DL3) being barium titanate, an example of thematerial of the first internal electrode layer 15 and second internalelectrode layer 16 being nickel, an example of the material of the basefilm for the first external electrode 12 and second external electrode13 being nickel, and an example of the material of the surface filmbeing tin, but the same effects as mentioned above can be achieved evenwhen the dielectric part 14 is made of a dielectric substance other thanbarium titanate, when the first internal electrode layer 15 and secondinternal electrode layer 16 are made of a metal or alloy other thannickel, when the base film for the first external electrode 12 andsecond external electrode 13 is made of a metal or alloy other thannickel, and when the surface film is made of a metal or alloy other thantin.

In the present disclosure where conditions and/or structures are notspecified, a skilled artisan in the art can readily provide suchconditions and/or structures, in view of the present disclosure, as amatter of routine experimentation. Also, in the present disclosureincluding the examples described above, any ranges applied in someembodiments may include or exclude the lower and/or upper endpoints, andany values of variables indicated may refer to precise values orapproximate values and include equivalents, and may refer to average,median, representative, majority, etc. in some embodiments. In thisdisclosure, any defined meanings do not necessarily exclude ordinary andcustomary meanings in some embodiments. Also, in this disclosure, “theinvention” or “the present invention” refers to one or more of theembodiments or aspects explicitly, necessarily, or inherently disclosedherein.

It will be understood by those of skill in the art that numerous andvarious modifications can be made without departing from the spirit ofthe present invention. Therefore, it should be clearly understood thatthe forms of the present invention are illustrative only and are notintended to limit the scope of the present invention.

We claim:
 1. A laminated capacitor comprising: a plurality of firstinternal electrode layers used as one polarity and a plurality of secondinternal electrode layers used as another polarity facing one anothervia a first dielectric layer contributing to the formation of capacityand also arranged alternately via the first dielectric layer; and afirst external electrode used as one polarity, to which edges of theplurality of first internal electrode layers are connected, and a secondexternal electrode used as another polarity, to which edges of theplurality of second internal electrode layers are connected; wherein atleast one additional first internal electrode layer, which has its edgeconnected to the first external electrode as do the first internalelectrode layers, is provided to only one of the plurality of firstinternal electrode layers so as to face one another via a seconddielectric layer having a thickness smaller than the thickness of thefirst dielectric layer and not contributing to the formation ofcapacity; wherein at least one additional second internal electrodelayer, which has its edge connected to the second external electrode asdo the second internal electrode layers, is provided to only one of theplurality of second internal electrode layers so as to face one anothervia a third dielectric layer having a thickness smaller than thethickness of the first dielectric layer and not contributing to theformation of capacity; and wherein the number of the first internalelectrode layers including the at least one additional first internalelectrode layer and the number of the second internal electrode layersincluding the at least one additional second internal electrode layerare each at least six.
 2. A laminated capacitor according to claim 1,wherein the relationship of a thickness td1 of the first dielectriclayer, a thickness td2 of the second dielectric layer, and a thicknesstd3 of the third dielectric layer satisfies td2≅td3<⅔×td1.
 3. Alaminated capacitor according to claim 1, wherein the laminatedcapacitor has a length L which is a measurement along the directionperpendicular to the laminated direction between the first and secondexternal electrodes, a width W which is a measurement along thedirection perpendicular to the laminated direction and alsoperpendicular to the length direction, and a height H which is ameasurement along the laminated direction, wherein L>W>H.
 4. A laminatedcapacitor according to claim 1, wherein the thickness of each seconddielectric layer and the thickness of each third dielectric layer are asthick as about 40% to about 70% of the thickness of each firstdielectric layer but are thicker than the thickness of each first andsecond internal electrodes.
 5. A laminated capacitor according to claim1, wherein the thickness of each second dielectric layer and thethickness of each third dielectric layer are about 0.5 μm to about 3.0μm and the thickness of each first dielectric layer is about 2.0 μm toabout 6.0 μm.